Don't look to politicians and high finance, it's pressure from below that will be the driver of change.

More than 146 countries covering 87% of global greenhouse gas emissions have now submitted their national pledges to tackle climate change in advance of the major climate summit in Paris. These are known as Intended Nationally-Determined Contributions. Note the language: these aren’t commitments and are only “intended”.

Since collectively these INDCs would still leave us on course for nearly 3℃ warming, some way beyond the 2℃ target that the international community has settled on as a safe threshold, the hope is that they will be ratcheted up at Paris and beyond.

But will countries stick to these pledges? And what happens if they don’t?

Climate negotiations have a long history of countries failing to deliver on their commitments. More than 16 countries failed to meet their targets under the first commitment period of the Kyoto Protocol up to 2012 and some major emitters like Canada simply reneged on their commitments without consequences.

But the problem of getting countries to implement their commitments is certainly not unique to climate change. Indeed it is a general feature of international relations that in the absence of a global police force and with weak judicial systems, there is no overriding central authority to force states to abide by national or international law. Essentially the only sanctions available are moral pressure (stigmatising non-compliant countries, as happens over human rights), trade sanctions (used to isolate governments such as the apartheid regime in South Africa) or military sanctions (applied to various countries in the Middle East in recent years).

Military sanctions are clearly not going to be applied in this case. Trade measures have been used in climate policy however, sometimes controversially, such as subsidies to solar and wind industries or so-called border tax adjustments, where countries impose a fee on products coming from markets where carbon is not regulated or taxed giving them an unfair competitive advantage.

It is moral pressure that climate diplomacy really relies upon though. This has pressured the EU to adopt and maintain a leadership role, for example in setting out a more ambitious target than that adopted by many other major industrialised regions. Often, however, even that is ineffective. The pariah status that the Bush government earned for walking away from the Kyoto Protocol had only minimal effect on the US’s position at the time. A change of administration ultimately brought about a shift in policy.

There have been calls in the past for more ambitious approaches to enforcing climate commitments. In 1997 Brazil proposed the establishment of a Clean Development Fund to fine countries failing to meet their emissions targets under the Kyoto Protocol. The funds generated from fines on richer (“annex 1” in UN language) countries would then have been distributed to poorer nations to meet their adaptation costs or fund local mitigation actions.

The proposal was vetoed and instead turned into the Clean Development Mechanism which allows richer countries to pay poorer ones to reduce emissions on their behalf. In a cunning political move, rather than targeting tougher compliance for richer countries, the solution became to pay poorer countries to comply instead.

In reality, the tools that will be used to hold governments to account for their climate commitments will be a combination of public and civil society pressure and the threat of litigation on behalf of those people affected by inaction, of which we have seen an increase in recent years. The Dutch government was subject to the first climate liability case in June 2015, but there have been earlier attempts by affected indigenous groups in the Arctic to bring cases against the US government over its lack of action on climate change. We will likely see more such cases in future.

This activism will increase thanks to a growing realisation of the gains to be made from moving rapidly to a lower carbon economy in terms of jobs, competitiveness and energy security. In other words, pressure from below is likely to be the driver of change as much as, if not more than, pressure from above.